null: fix memory leak of kvargs
null: fix memory leak of kvargs

'struct rte_kvargs' is allocated in rte_kvargs_parse(), and should be
freed with rte_kvargs_free().

Reported-by: John Mcnamara <af31595c36a4239b9676e9b3a777d3e2f15a6c4d@intel.com>
Signed-off-by: Tetsuya Mukawa <b347a9f5840345582b30d055e1e99ac6ac7bce3c@igel.co.jp>
Acked-by: Neil Horman <3316dc2d77df57653443c0391a5296176d6ca9c3@tuxdriver.com>

phermansson/dpdk,phermansson/dpdk,phermansson/dpdk,phermansson/dpdk